[PATCH 08/15] KVM: arm64: Select debug state to save/restore based on debug owner

[Oliver Upton <oliver.upton@linux.dev>]

Select the set of debug registers to use based on the owner rather than
relying on debug_ptr.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/include/asm/kvm_host.h         | 21 +++++++++++++++++++++
 arch/arm64/kvm/hyp/include/hyp/debug-sr.h |  8 ++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index d76e4e44b65b..2d9aee66d5d4 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1357,9 +1357,30 @@ void kvm_handle_debug_access(struct kvm_vcpu *vcpu);
 #define kvm_vcpu_os_lock_enabled(vcpu)		\
 	(!!(__vcpu_sys_reg(vcpu, OSLSR_EL1) & OSLSR_EL1_OSLK))
 
+#define kvm_debug_regs_in_use(vcpu)		\
+	((vcpu)->arch.debug_owner != VCPU_DEBUG_FREE)
 #define kvm_host_owns_debug_regs(vcpu)		\
 	((vcpu)->arch.debug_owner == VCPU_DEBUG_HOST_OWNED)
 
+#define vcpu_debug_regs(vcpu)					\
+({								\
+	struct kvm_guest_debug_arch *__d;			\
+								\
+	switch ((vcpu)->arch.debug_owner) {			\
+	case VCPU_DEBUG_FREE:					\
+		WARN_ON_ONCE(1);				\
+		fallthrough;					\
+	case VCPU_DEBUG_GUEST_OWNED:				\
+		__d = &(vcpu)->arch.vcpu_debug_state;		\
+		break;						\
+	case VCPU_DEBUG_HOST_OWNED:				\
+		__d = &(vcpu)->arch.external_debug_state;	\
+		break;						\
+	}							\
+								\
+	__d;							\
+})
+
 int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu,
 			       struct kvm_device_attr *attr);
 int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
diff --git a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
index d00093699aaf..acc47f77b3d0 100644
--- a/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/debug-sr.h
@@ -132,13 +132,13 @@ static inline void __debug_switch_to_guest_common(struct kvm_vcpu *vcpu)
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
-	if (!vcpu_get_flag(vcpu, DEBUG_DIRTY))
+	if (!kvm_debug_regs_in_use(vcpu))
 		return;
 
 	host_ctxt = host_data_ptr(host_ctxt);
 	guest_ctxt = &vcpu->arch.ctxt;
 	host_dbg = host_data_ptr(host_debug_state.regs);
-	guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
+	guest_dbg = vcpu_debug_regs(vcpu);
 
 	__debug_save_state(host_dbg, host_ctxt);
 	__debug_restore_state(guest_dbg, guest_ctxt);
@@ -151,13 +151,13 @@ static inline void __debug_switch_to_host_common(struct kvm_vcpu *vcpu)
 	struct kvm_guest_debug_arch *host_dbg;
 	struct kvm_guest_debug_arch *guest_dbg;
 
-	if (!vcpu_get_flag(vcpu, DEBUG_DIRTY))
+	if (!kvm_debug_regs_in_use(vcpu))
 		return;
 
 	host_ctxt = host_data_ptr(host_ctxt);
 	guest_ctxt = &vcpu->arch.ctxt;
 	host_dbg = host_data_ptr(host_debug_state.regs);
-	guest_dbg = kern_hyp_va(vcpu->arch.debug_ptr);
+	guest_dbg = vcpu_debug_regs(vcpu);
 
 	__debug_save_state(guest_dbg, guest_ctxt);
 	__debug_restore_state(host_dbg, host_ctxt);
-- 
2.39.5